Cellulose is an organic compound, polysaccharide, consisting of a linear chain of several D-glucose units linked through β(1,4) glycosidic bonds. Many properties of cellulose depend on its chain length or degree of polymerization, the number of glucose units that make up one polymer molecule. Cellulose is mainly obtained from wood pulp and cotton but may be also secreted by some species of bacteria to form biofilms.
Microfibrillated cellulose (MFC) or nanocellulose is a material composed of cellulose fibrils, i.e. basic structural components of wood with a high length to diameter ratio (aspect ratio). The microfibrillated cellulose can be prepared from any cellulose containing material including wood (pulp fibres).
Generally, the cellulose fibrils are used in cosmetic compositions e.g. as a composite coating agent for hair, eyelashes or nails. Microfibrils are used, for example to improve the lengthening of the eyelashes. Microfibrillated cellulose may also be used as a binder or filler for solid dosage forms and as a bodying agent or a drug carrier in topical formulations or dermatological products. Additionally, cellulose fibrils may be used as a stabilizer for surfactant free oil-in-water emulsions.
European patent EP 820267 and the corresponding U.S. Pat. No. 6,001,338 disclose the use of an aqueous solution or dispersion of a film-forming polymer and an aqueous suspension of natural cellulose microfibrils as a composite coating agent for hair, eyelashes, eyebrows and nails. The aim is to use cellulose microfibrils in cosmetics to improve the physical properties of cosmetic compositions.
Publication US 2002/192251 deals with cosmetic compositions, especially mascara, intended for human keratinous substances such as the skin, nails or keratinous fibers (eyelashes, eyebrows and hair) and containing a mixture of cellulose nanofibrils or microfibrils with second fiber and wax.
Up to now, in connection with human body, microfibrillated cellulose has only been proposed for enhancing properties of cosmetic formulations.
The skin is made up of layers of epidermis, dermis and subcutis. The epidermis is the outer layer of the skin and consists of sublayers: stratum corneum, granulosum, spinosum and basal layer. Keratinocytes are the main type of cells which make up the epidermis. The dermis is the middle layer of the skin and is held together by collagen made by fibroblasts. The subcutis or a subcutaneous layer is the deepest layer of the skin and consists of a network of collagen and fat cells.
There are a number of causes for skin inflammation (dermatitis), e.g. irritants such as some chemicals, overexposure to sun; infections; chronic or acute inflammatory conditions.
There are chronic and inflammatory skin conditions and disorders like atopic dermatitis, a type of eczema, for which there is currently no cure available. For controlling the symptoms, various treatments may be used, such as topical treatments focusing on reducing both dryness and inflammation of the skin, e.g. moisturizers. However, the moisturizers should not have any ingredients that may further irritate or aggravate the skin condition. Also topical corticosteroid products may be used. However, using steroids involves disadvantages, such as thinning of the skin. High potency steroids should also be avoided on the face or other areas where the skin is naturally thin. If there are also infections involved, antibiotics may be employed.
There remains a need for improved and efficient products comprising dermatological compositions with an anti-inflammation activity which allow local treatment of different chronic skin disorders, such as atopic dermatitis and psoriasis, while at same time avoiding the side effects and disadvantages of conventional treatments.